All band television antenna



| H. FINNEBURGH, JR 9 ALL BAND TELEVISION ANTENNA I 3 Sheets-Sheet 1 Oct; 13, 1953 Filed March 10, 1953 PRIOR ART ANTENNAS & M /Ww R E 3 m 3 b 0 K H. k hr vm MUH w 4 0L 4 Oct. 13, 1953 L. H. FINNEBURGH, JR 2,655,

ALL BAND TELEVISION ANTENNA Filed March 10, 1955 s Sheets-Sheet 3 7 87 as sfaa A 1021,

c d 4 f lZZ /z/1 .lZ/a/ /z/ I25 INVENTOR Lewis H. Finneburgh Jr.

ATTORNEY Patented Qct. 13, 1953 UNITED STATES PATENT OFFICE 30 Claims.

This invention relates to antennas for radio and television broadcasting and reception, and particularly to antennas of the collinear type in which a series of longitudinally spaced conductors are connected for substantially in-phase operation.

With all antennas of which I am aware, maximum response is obtained over a limited and generally a relatively narrow portion of the range of frequencies useful for radio and television broadcasting. For many purposes, this is not objectionable; in fact, it is frequently an advantage. However, in the case of antennas for television reception, for instance, it is generally desirable that the greatest possible response be obtained over the entire range of frequencies em ployed for television broadcasting. Though this may not be important in some localities where broadcasts receivable from stations within a reasonable distance from the antenna are confined to closely adjacent frequency bands, it is still important to the antenna manufacturer desiring to produce one standard antenna that is satisfactory for all or most geographical areas.

Another problem for the television antenna manufacturer, and one which is of concern to a large proportion of the ultimate customers, is to produce an antenna having high directivity. This is necessary in order to minimize interference with broadcasts from a station toward which the receiving antenna is directed by broadcasts from other nearby stations operating on the same or closely adjacent wave bands, but located in different directions from the receiving antenna.

Still another problem is to produce an antenna having as much gain as possible in order to bring in broadcasts emanating from relatively distant points. This is particularly important to television reception in the rural or fringe areas that are relatively remote from the stations whose broadcasts are to be received.

'All three of these problems have been and continue to be important where the receivable broadcasts are confined to the so-called very high frequency (V. H. F.) ranges. With the advent of broadcasting over the so-called ultra high frequency (U. H. F.) bands as well, the magnitude and acuteness of these problems has grown apace. In a constantly increasing number of localities, obtaining high gain and directivity over very wide ranges of frequencies is an essential requirement for satisfactory television reception.

Much work has been done in an effort to solve all of these problems as the television'industry has grown, and much has been accomplished.

However, up to the present time, no single antenna of which I am aware has proven satisfactory.

for television reception over the entire V. H. F. range and also over any substantial part of the U. H. F. range. For example, in my U. S. Patents No. 2,566,287, granted August 28, 1951, for Television Antenna System and No. 2,630,531, granted March 3, 1953, for Television Antennas, I disclosed an antenna of the collinear type that admirably solves all three of the foregoing problems over all the bands of frequencies utilized by channels 2 to 13 inclusive of the present V. H. F. range. The same antenna, made on a reduced scale, is equally well adapted for operation in the U. H. F. range, whether in the form of the 2-bay collinear antenna illustrated in the afore-' mentioned patents or in the more common com-' mercial form of a vertically stacked air of identical 2-bay units. However, this antenna has limited utility for U. H. F. when designed for V. H. F. and vice versa.

Nevertheless, the collinear type of antenna has outstanding gain and directivity characteristics which it would be highly desirable to achieve in a single unit having a sufficiently broad-band response to be used effectively over both the V. H. F. and U. H. F. frequency ranges.

Accordingly, the principal object of the present invention is to provide ,a collinear type ofantenna having high gain characteristics in both the V. H. F. and U. H. F. frequency ranges.

More specifically, it is an object of the invention to provide a collinear type of antenna which will operate with high gain over as much as possible of the frequency ranges of both the V. H. F. and U. H. F. broadcasting channels.

Still another object of the invention is to accomplish the foregoing while retaining, to the greatest extent possible, the high degree of directivity that is characteristic of known collinear antennas.

By means of the present invention, these objectives have been accomplished with unusual success; and the principles employed may be utilized with appropriate variations in physical dimensions and electrical values to obtain comparable results in other and additional frequency ranges. I

The invention is characterized in part by the utilization of a plurality of separated, collinear, conductors of substantially equal resonant lengths. Three such elements in a single collinear array, dimensioned for maximum response as half-wave radiating elements in a selected intermediate frequency range, are generally preferred, though four or more collinear conductors may be employed. The collinear array is preferably driven through a two conductor transmission line connected to feed points adjacent the geometrical center of the array, though other driving systems may be used in accordance with well-known principles. By bridging the discontinuities or gaps between adjacent ends of the separated collinear elements in such an array with circuits that are anti-resonant at the fundamental frequency of the individual collinear elements, substantially in-phase operation is ob,- tained with consequent high gain at that fundamental frequency, and over a limitedvrangeaborve; and below the fundamental frequency. Also, the plurality of collinear elements, so connected; operate as a unit in the manner of a single; halfwave dipole at about /3 the fundamental frequency of the individual collinear elements (depending on the impedance at the lower frequency at the circuits that bridge the gaps: between adijacent collinear elements), and: over a.- limited frequency range above and: below that. value. By: proportioning the separated collinear elements to have a fundamental frequency in; about the center of. the high portion of the V. H. F. range (174to 216 megacycles) such an array also acts asv a half-wave dipole in a lower range which, by proper design, may be the lower portion of the V. H. F. range (5ito 88 megacycles). This relationship has been employed, in conjunction with certain additional features, in the antenna dis.- closed and claimed in my above-mentioned patents.

The present invention also causes such an army to act as a three element. collinear antenna. in a third range. of higher frequencies, such as. the. U. H. F. range (470 to 890 mcgacycles), by modifying the centermost collinear element or elements of the array. a pair of gaps in the centermost element or elements and by bridging each of these gaps with. a circuit that is anti-resonant at, say, three: times the fundamental frequency of the individual collinear elements. Thus the centermost element. or elements may comprise a plurality of: separated collinear sections that are individually resonant as half-wave element at frequencies in the U. H. F. range and that are connected together by anti-resonant circuits selected to produce substantially in-phase operation of these. three sections at their fundamental U. H. F. fre

quency.

In U. S. Patent No. 2,282,292 to Amy and Aceves, a pair of anti-resonant circuits are interposed in a half-wave dipole for the purpose of creating an infinitely high impedance at certain selected frequencies. However, the location of these anti-resonant circuits along the length of the dipole is such that the portions of the an.- tenna disposed outwardly in opposite directions beyond the anti-resonant circuits are not resonant at these selected frequencies. As a result. the anti-resonant circuits either act as metallic insulators to substantially cut oif or isolate the outer portions of the antenna at the frequencies at which their impedance is infinite, or they act substantially as ordinary conductors of relatively low impedance at other frequencies, and never function as phase reversing circuits to produce in-phase operation of the separated sections of the antenna as half-wave collinear elements.

In accordance with the present invention, one pair of anti-resonant circuits functions in a low frequency range a .low impedance conductors.

This i done by providing in the manner suggested by Amy and Aceves, but in an intermediate frequency range they function as phase reversing circuits, rather than as insulators; and the other pair of anti-resonant circuits function in the low and intermediate frequency ranges as low impedance conductors, but in a still higher frequency range they also function as phase reversing circuits. Depending upon whether or not a particular frequency of operation in the highest frequency range closely approaches a harmonic of the fundamental frequency in the intermediate frequency range, the outer portions of the antenna may or may not be substantially cut-off at such frequency of operation. However, possibly because of the distanceofthose outerportions of the antenna from the-preferredv central feed point, their effects on the operation of the antena in the highest frequency range are generally relatively small. They tend to produce undesirable minor lobes n. the directiyity pattern of the antenna at certain points in thehighest frequency. range, but.

at the same time, they seem to enhance, the broad-band characteristics of the antenna. in that frequency range.

Other objects, advantages, and characteristics of the present invention will become apparent fromthe following explanation of the principles utilized in the invention and the. detailed d e. scription of several. illustrative embodiments of the invention, considered in conjunction with the accompanying drawings.

In the drawings, to assist in explaining the theory and mode of operation of the invention, certain priorart antennas; are shown in Figs. 1, and 2; and the several embodiment of the pres! ent invention are shown in Fig. 3 to 14.

Fig. 1 is a diagrammatic illustrationv of a con; ventional, three-element, collinear antenna in which adjacent of collinear elements are connected together byanti-resonant circuits in the, form of so-called quarter-wave, shorted or phase. reversin stubs;

Fig.. 2 is a diagrammatic illustration of a con-. ventional half -wa ve dipole antenna that has been modified by inter-posing anti-resonant circuits in the two arm of the dipole, each of the anti? resonant circuits, in this case, being in the form of a 100;). having an inductor and a capacitor in parallel, as disclosed in the above-mentionedPatent. No. 2,282,292 to A y a d Aceves;

Fig. 3 isa diagrammatic illustration of a threeelement collinearantenna similar to the one shown in Fig. 1, but modified in accordance with the present invention by the insertion of an additional pair of anti-resonant circuits in the cen tral element of the three-element collinear are ray;

Fig. 4 is a diagrammatic illustration of a threeelement collinear antenna similar to the one illustrated in Fig. 3 but employing, as phase reversing means, the same kind of antirresonant circuits employed for a different purpose in the antenna of Fig. 2;

Fig. 5 is a diagrammatic illustration in elevation showing the application of the invention to an antenna comprising two vertically spaced arrays, each containing three main collinear elements spaced apart and bridged by main phase reversing stubs with the main stubs of the upper array disposed in back-to back relationship with the main stubs of the lower array and with additional stubs applied to the. central collinear element-of each array to render the antenna responsive in an additional higher frequency range;

Fig. 6 is a fragmentary plan view of an antenna similar to the one in Fig. 5, but with the additional stubs incorporated in the central 001- linear element of each array extending in a horizontal plane rather than in a vertical plane to facilitate collapsing of the antenna for packag- 111g;

Fig. 7 is a plan view of a unitary conductor suitable for substitution in the antenna of my Patents Nos. 2,566,287 and 2,630,531 in place of the portion of the central collinear element in each array extending laterally to either side of the center feed gap, four such unitary conductors being required to convert the antenna of my said patents to one conforming to the antenna of Fig. 5 in accordance with the present invention;

Fig. 8 is an elevation of the antenna conductor of Fig. '7 as viewed from the front of the antenna in which it is intended to be installed;

Fig. 9 is a diagrammatic illustration in elevation showing the application of the invention to a modified form of the antenna of Fig. 5;

Fig. 10 is a fragmentary plan view showing an optional angular relationship in a horizontal plane of the generally collinear radiating elements of the antenna of Fig. 9.

Fig. 11 is a fragmentary diagrammatic illustration in elevation showing the application of the invention to still another modified form of the antenna of Fig. 5;

Fig. 12 is a diagrammatic illustration of a fourelement collinear antenna modified in accordance with the present invention by the insertion of an anti-resonant circuit in each of the centermost collinear elements;

Fig. 13 is a diagrammatic illustration in elevation showing the application of the invention to still another modified form of the antenna of Fig. 5; and

Fig. 14 is an electrical current diagram showing the current relationships in the antenna of Fig. 13 when operating at each of its three optimum frequencies.

Referring to Fig. 1 of the drawings, the antenna diagrammatically illustrated therein comprises three collinear elements I, 2, and 3 of suitable conductor material, the central element I being connected adjacent its mid-point to the leads 4 and 5 of a two conductor transmission line. In the form shown, the central element I has a gap 5 at its mid-point which preferably is quite small compared to the length of the elements, and the transmission line leads 4 and 5 are connected at opposite ends of this gap to the two parts it: and Ib of the central element I. However, it will be understood by those skilled in the art that the employment of a gap 6 is not essential and that the central element I may be a continuous conductor, in which case the leads,

4 and 5 are connected in substantially the same centrally spaced location, possibly through an impedance matching device.

The collinear elements I, 2, and 3 are normally and ideally of the same resonant length, which is V2 the fundamental wave length for which the antenna is designed. As shown, the collinear elements are separated by gaps I and 8 that are also preferably quite small compared to the resonant length of the collinear elements themselves. Bridging the gaps and 8 are quarterwave shorted stubs 9 and II! which are preferably designed, in accordance with well-known principles, to have a developed length roughly equal to the length of the individual collinear elements and maximums (substantially infinite) impedance at the fundamental resonant frequency of the individual collinear elements. When so dimensioned, the stubs may be most aptly characterized as anti-resonant circuits at that fundamental frequency. When a plurality of generally collinear elements connected by such circuits are of substantially the same resonant length, currents of the fundamental resonant frequency in the collinear elements are in-phase and maybe represented by the fragmentary sine wave curves I2 in Fig. 1. Thus, the stubs 9 and I0 cause the resonant currents in all three collinear elements I, 2, and 3 to be in-phase, thereby greatly increasing the gain of the antenna compared to a half-wave dipole tuned to the same frequency.

When the antenna of Fig. 1 has a current of approximately its fundamental frequency (three times the fundamental wave length), imposed upon it, the stubs 9 and II) are no longer anti-resonant and act merely as conductors having a relatively low impedance. This causes the antenna to function as a half-wave dipole at the lower frequency, and the current in the antenna may be approximately represented by the curve Il. (Note: current representations in the drawing are not intended to represent the relative magnitudes of the currents.) In practice, the curve I1 will not conform exactly to a sine wave, but will be distorted at the stub locations to a degree depending upon the impedance of the stubs at the frequency of the current I1.

While this analysis necessarily assumes many ideal conditions that are never quite achieved in practice, small deviations from ideal dimensional and electrical values cause only correspondingly small deviations in the actual performance ofa physical antenna. Similarly, though the description of the performance characteristics could be precisely accurate only for a single resonant frequency for each of the two modes of operation described, approximations of such characteristics are achieved in practice in spite of a moderate deviation either way from the optimum frequency. As a result the antenna of Fig. 1 will operate essentially as described over a moderate frequency range embracing the optimum frequency of the current I1, and over a comparable frequency range embracing the optimum frequency of the current I2.

Referring next to Fig. 2, there is diagrammatically shown a half-wave dipole antenna which is driven adjacent its mid-point by a two conductor transmission line, having leads II and I2 connected on opposite sides of a central gap I 3, the same as in Fig. 1; In this case, the antenna from tip to tip may be viewed as a single halfwa've conductor I4, its length being selected so that it is resonant as a half-wave conductor to a particular, relatively low frequency. A current of this frequency imposed upon the antenna is approximately represented by the curve Ix (again ignoring deviations from a true sine wave due to y the relatively low impedance of circuits I5 hereafter described).

interposed in the conductor I 4 on opposite sides of the leads I I and I2 are a pair of anti-resonant circuits I5, each of which consists of a loop which may include an inductor I1 and a capacitor I8. The gaps in which the anti-resonant circuits I5 are interposed are exaggerated in length in the drawing and are preferably quite small compared to the length of the antenna or any of its sepa- 7 rated portions. In the following discubsiom the lengths of these gaps are assumed; tobcnegligible and are ignored for simplification.

m shown, the anti-resonant circuits I5 are interposed so that the effective conductor length between them, comprising identical portions Ila and Ilb and the center gap I3", are about twice the length of each of the identical, individual, extreme conductor portions designated He and Md. So long as the. length of each outer portion Ne and: Md is substantially different (longer or shorter)- than the combined length of the inner portions Ila and Ill). the mode of operation is essentially the same (except for certain harmonic conditions mentioned below). The values of inductance and capacitance for the circuits I 5 are selected according to known principles so that both circuits are anti-resonant (i. e. have substantially infinite impedance) at the. frequency for which the conductor between them (comprising the portions Ila and Nb) is resonant.

If the fundamental resonant length of the central conductor portions Ila plus Mb (e. g. 2.5 meters) is substantially different from the individual resonant lengths of the extreme conductor portions Ito and Ild (e. g. 1.25 meters), the circuits I5 function as insulators at the frequency at which the central conductor portions Ila plus Ilb are resonant, thus cutting off the extreme conductor portions I40 and Md. At substantially different frequencies, however, the impedance of the anti-resonant circuits I5 is relatively low, and they function as conductors of relatively low impedance, giving the antenna an effective resonantv length roughtly corresponding to its over-all physical length. Thus, the antenna functions as a half-wave. dipole at the frequency corresponding to its over-all resonant length, the current therein being represented by the sine wave curve Ix; and at a higher frequency corresponding to the" resonant length of the central portions Ila plus Ilb, the. antenna functions as a shorter half-wave dipole, the extreme conductor portions Ilc and Ild being inoperative and the current in the central portion being represented by the sine wave curve 1,.

Exceptions to the above-described mode of operation of the antenna of Fig. 2 occur only if the fundamental resonant length of the outer conductor portions Ito and Ild is. a whole multiple of the fundamental resonant length of the inner portion Ma plus Ilb (i. e. the fundamen tal resonant frequency of I40 and Md is 1, or or V3, etc. of the fundamental resonant frequency of Ida plus I Ib). When designed to have any such proportional relationship of its parts, the outer portions I4c and Md will not be cut-oil, and many different harmonic response conditions are obtained. For example, when I I0 and Ild are both of the same resonant length as Ila plus MD, the antenna of Fig. 1 is obtained.

A number of variations of the antenna of Fig. 2 are disclosed in the above-mentioned patent of Amy and Aceves. In all of those variations, however, whatever the frequency of operation, the antenna functions only as a dipole of variable length. The function of the anti-resonant circults employed is merely that of "dividers" for automatically adjusting the length of the dipole according to the frequency of the imposed wave. The same would be true if stubs, such as 9 in Pig. 1, of appropriate physical dimensions, were to be substituted for the inductor-capacitor loops Ii in the antenna of Fig. 2.

Only in the event that the conductor portions 1 He met Md one each. of substantially the so resonant length as the combined central conductor'portions Haplus Mb; could the anti-resoulnt circuits in the antenna; of Pig 2 produce in-phun collinear operation of the separated aligned condoctors as half-wave elements. In this case. the inductor-capacitor loops I5 would be tuned to the same frequency to which each of the three antenna portions separated thereby is resonant (i. c., He plus Ill), and Ike, and lid) and would function substantially as phase reversing. stubs, causing the entire antenna to operate as a threeeiementcollinear antenna of the character shown in Fig. 1.

From the foregoing. discussion of the basic differences' and superficial similarities of the amtennas'. of. Figs. 1 and 2, it will be recognized tilt. in the dipole antenna of Fig. 2, the anti-resonant circuits are utilized only to cut oil the outer portions Ho and Md of the antenna when it is operating at the resonant frequency of the inner portion Ha plus Nb. By contrast, when the same or equivalent anti-resonant circuits are employed to connect adjacent conductors of substantially equal resonant length in the collinear antenna of Fig. 1, the anti-resonant circuits, instead of cutting off the outer portions 2 and 2 01' the antenna at the resonant frequency of the central element I, actually couple the outer elements with the inner element for in-phase operation as three half-wave collinear conductors. In both antennas (ignoring the harmonic relationships described above), the anti-resonant circuits operate essentially as ordinary conductors at frequencies substantially above or below the fundamental frequency to which they are tuned, with a relatively low, variable impedance that is either inductive or capacitive in character depending on the particular frequency of operation.

Referring now to Fig. 3, the present invention may be applied to a conventional, three-element, collinear antenna of the type shown in Fig. 1 by modifying the central element, generally designated 2|, of the collinear array. The three collinear elements 2I, 22, and 23 are of substantially the same resonant length, and the central element 2 I is driven adjacent its mid-point by a two conductor transmission line having leads 2 and 25 connected on opposite sides of a center feed gap 26. Gaps 21 and 28 separating the three collinear elements 2I, 22, and 23, are bridged by quarter-wave shorted stubs 29 and 30.

In accordance with the invention, the central element M is provided with an additional pair of gaps 3| and 32 that may be located to divide the central element 2I into three collinear subelements 2I a, 2Ib, and 2Ic, also of substantially equal resonant lengths. Additional stubs 33 and 34 bridge the gaps 3| and 82, respectively, and may be dimensioned to be anti-resonant at substantially the resonant frequency of the individual sub-elements 2Ia, 2Ib, and 2Ic.

The presence of the additional gaps 3| and I2 and stubs 33 and 34 causes the resonant length of the entire central element 2I to be somewhat greater than that of a straight conductor of the same tip-to-tip length. In all of the antennas illustrated, the central feed gap also has a similar, small effect on the resonant length. Accordingly, if accurate matching of resonant lengths is desired, it may be necessary to take this into account and make appropriate minor adjustments in the physical lengths of the various conductors.

In the light of the description of the mode of operation of the antenna of Fig. 1,it will be apparent that the small stubs .33 and 14in Fig. 3 will have substantially infiniteimpedanceat the fundamental frequency of each subcollinearelemen-t 21a, 24b, and 21c. At the much lower fundamental frequency of the collinear elements-22!, 22, and 23, and at the still lower fundamental frequency of a half-wave dipole comprising all three of the main collinear units, however, the impedance of the small stubs 3.3 andM will (be very 10W. Similarly, the large stubs 28 and 30 will have substantially infinite impedance at the fundamental frequency of the main collinear elements 2-], 22, and 23, but relatively low-impedance at most other frequencies.

Since the subcoll-inear elements 24a, 21b, and 21-0 are of substantially the same resonant length, it will also be understood that, at theirhi-gh resonant frequency, the small stubs 33 and 34 function not as mere insulators, 'but'as phase reversing circuits causing iii-phase operation of the subcollinear elements as a'high frequency collinear antenna. *Under these conditions, the currents in the subcoll-inear elements are represented by the sine wave curves Is. At the intermediate resonant frequency of the main collinear elements 2 l, 22, and "2%, however, the small stubs 33 and 34 function as conductors of relatively low impedance and the main stubs Hand 3!! as phase reversing circuits ca-using in-phase operation of the main collinear elements *as an intermediate frequency collinear antenna. In this case, the currents in the antenna are represent-ed by the sine wave curves I2. Finally, at

the low resonant frequency of a half-wave dipole comprising the elements =21, :22, and '23, all of the stubs function as conductors of relatively low impedance, and the antenna as a whole functions as a half-wave dipole, the current in the antenna then being represented by the wave curve 11.

It is particularly to be noted that, if the impedan'ces and resonant lengths of the various conductors are properly matched so that-the frequency 0f Is is substantially three times t the frequency of I2 '(a harmonic ,relation'ship"), the impedance of the main stub-s ZS- and 30 will again become substantially infinite and these stubs will become Wave phase reversingstubsiwith currents in the collinear elements approximately represented iby'the curves hi1. "Thus,cven at-the high fundamental resonant "frequency of subelements 2'2 41, '2 It, and 210, the outer elements 22 and 123 are not cut off and may contribute somewhat to the gain at this frequency. .At frequencies above and below the fundamental frequency of the 'sub-elementsil'ia, zlb, andfzlc (but still of the same order of magnitude), many different current relationships exist.- In this case, the presence of the main stub-s :29 (and!!! and the outer elements and 23 seems 'tohave a broad-banding efiect on the antenna in the general range of the frequencies of the current Is. This broad-banding effect i notyetfullyun'derstood from available performance data and other electrical measurements made, but the "result is highly beneficial and is particularly pronounced in the multiple bay antennas illustratedinfliijgs. 4 to '12 inclusive.

The value 'of the antenna of Fig. 3 for television reception is greater than "mightbe expected because of the fortuitous relative location in the radio frequency spectrum of the low and high sections of "the established V; television band and of the U. H. television ba-nd. As noted above, the low -Fxband runs from 54to.88-mc., the center of this hand being about '70 me. The high V. H. F. band runs from 174 me. to 216 mc., the center of this band being about 195 me. .or only slightly less than three times the frequency of the center of .the low :F. band. The U. H. F. bands runs from .470 me. to 890 mc., the center of this izand being -about680 me. .or only slightly greater than three times the frequency of the center of the hig F. band.

Looking now at the relative wave lengths of the currents ll, I2, and .13 in Fig. :3, it will :be observed that the wave length of I2 is about onethird, the wave length 0th .50 that the frequency of =12 is about three times that of I1. Similarly, the frequency oflsis about three times that of I51. Thus, if the main .collinear elements 2.1, 22, and are maderesonant to about 2.00 mc., the half-wave dipole comprising the entire antenna will be resonantto about 67 mc., and the subcollinear elements 2|.a, 2.11), and 210 will be reso- :nant to about 1600mm Therefore, these resonant frequencies of the antenna, in the order named, fall close to the centers of the high V. '1. band, the low V. H. F. band, and the U..H. F.

band, respectively. From this relationship, it will beimmediately obvious that the three different frequencies to which the antenna of Fig. .3 will give maximum response, are practically the ideal frequencies to make the antenna of the greatest possible value for all three television bands. So

long was the main collinear. elements 2 l, :22, and 23 and-stubs 29 and 310 are dimensioned .so that the frequency .of the optimum current I2 is in the range from about 174 to 216 me. .(in the high portion of the V. F.1band), the various other physical and electrical values .may beso adjusted that the frequency of thecurrent I1 Will be some place Within the low portionof the V. H. F.'range 454-188 mo.) and the frequency of the current Ia will be some place .within the U. H. F. range (470-890 :mcu). Accordingly, inal'l of the various embodiments of'the present invention, for :te'levision reception purposes, the main elements .21,

-22, and :23 .and stubs -29 andz3fl i-may advantageonsly be designed tor optimum Jim-phase operation at :a frequency in the range from about Another fortuitous advantage of the antenna .of Fig. .3 is the little understood broad-banding effectof the :main stubs 129 and 30 and outerelevTm-cuts F22 and'23 at frequencies above and below the irequencycof 13 in the U. H. F. range. This extends the usefulness of the antenna over a larger part ,of this relatively broad range -from 470 to 890 .megacycles.

A further outstanding feature of the antenna of Fig. 3 is the ease with which the :point of maximum response in the U. H. F. band may be varied-as may be desired indifferent geographi- ..-cal areas. fi hough'ithe exact explanation isfby -=apa1ft flowers the frequency of maximum response.

Small changes in the developed length of the stubs '33 and 34 and in the lengths of the gaps 62652 1, 28,31, and 32 :m-a-ybe made to efiec-tsimilar changesin-performance in theU. band. Thus, though I have illustrated and described the antenna of Fig. 3 as having the stubs 38 and 11 34 ideally located in the center element so that the sub-collinear elements Zia, 2|b, and 2|c are of substantially the same resonant length, this relationship is not essential and may be advantageously varied to a considerable degree. Similarly the point of maximum response may be shifted and the flatness of the gain curve in the high V. H. F. band may be increased or decreased within limits by slight alterations in the various relative dimensions of the collinear elements 2|,

' 22, and 23 and the stubs 29 and 30. Accordingly,

it should be understood that the several relationships between the frequencies to which the elements are tuned, which are determined by their relative physical dimensions, need only approximate the theoretically ideal relationships. References to such relationships in the appended claims, therefore, should be interpreted accordingly.

Referrin now to Fig. 4, the antenna illustrated therein is identical with that of Fig. 3, except for the substitution of correspondingly tuned inductor-capacitor loops 39, 40, 43, and 44 for the large stubs 23 and 30 and for the small stubs 33 and 34. Therefore, the antennas of Figs. 3 and 4 are substantially equivalent electrically and no further description of Fig. 4 should be necessary.

As explained above, quarter-wave shorted stubs (approximately half-wave developed lengths) and appropriately tuned inductor capacitor loops may be interchanged without altering the general mode of operation of the antenna. It should also be noted that several specific forms of inductorcapacitor loops may be employed, as shown in Figs. and 6 of Patent No. 2,282,292 to Amy and Aceves, mentioned above. Still other variations of these anti-resonant circuits may be employed, as will be recognized by those skilled in the art. However, both because of greater economy of manufacture and structural simplicity, I prefer to employ quarter-wave shorted stubs as antiresonant circuits for the purpose of the present invention.

From the foregoing disclosure, it will be appreciated that this invention extends the range of usefulness of a three-element collinear antenna by converting it from one responsive in only two frequency ranges to one responsive in three frequency ranges, while retaining all of the other desirable characteristics of this type of antenna. It will also be appreciated that the relationship of the three ranges is ideal for rendering the resulting antenna of the greatest possible value in all three of the sepaarted frequency ranges now employed for television broadcasting.

Referring next to Fig. 5, this figure illustrates the application of the present invention to the antenna described and claimed in my prior Patents 2,566,287 and 2,630,531. For simplicity, the reflectors, the supporting structure, and the collapsing feature disclosed in those patents have been omitted from Fig. 5, and only the basic electrical circuit is shown.

The antenna of Fig. 5 comprises identical upper and lower arrays, each including three main collinear elements 5|, 52, and 53. The antenna is driven through a pair of parallel transverse feeders 54 and 55 that are connected to the central collinear element 5| of each array at opposite sides of a center feed gap 56 therein. The transverse feeders are preferably approximately the same length as the individual collinear elements 5|, 52, and 53, and the leads 68 and 69 of a two-conductor transmission line are respectlvely connected to the mid-points of the transverse feeders 54 and 55. Additional pairs of parallel transverse conductors GI and 62 are respectively connected to the adjacent ends of the collinear elements of the upper array at opposite sides of the gaps 51 and 58 therebetween, and to corresponding points on the lower array. A shorting conductor 63 is connected across the mid-points of each pair of transverse conductors BI and 62, thus forming a common shorting element for a pair of oppositely facing, phase reversing stubs which function as anti-resonant circuits for the upper and lower arrays.

The central collinear element 5| in each array is provided with additional gaps 64 and 65 on opposite sides of the feeder conductors 54 and 55, and these gaps are respectively bridged by antiresonant circuits in the form of small shorted stubs 66 and 61. In this case, the gaps 64 and 65 in each central collinear element 5| are so located that the central sub-element 5|a of each central element 5| is slightly more than twice the length of the outer sub-elements 5|b and 5|c thereof. The developed length of the small stubs 66 and 61 may be selected to make them anti-resonant at a frequency in the range in which the sub-elements 5|a, 5|b, and 5|c are resonant as half-wave elements. In most cases, however, for reasons that will be explained, the small stubs 66 and 61 should be designed to be anti-resonant at approximately the frequency at which the central sub-element 5|a is resonant as a half-wave element.

The mode of operation of the antenna of Fig. 5 is essentially the same in most respects as a pair of vertically stacked antennas of the type shown in Fig. 3, connected in parallel. Accordingly, to that extent, its mode of operation has already been sufliciently described. One difference in operation is due to the back-to-back relationship of the main phase-reversing stubs of the upper and lower arrays, with the shorting conductors 63 forming common elements of the oppositely facing pairs of main stubs. As disclosed in my prior Patents 2,566,287 and 2,630,531, this has a remarkable broad-banding effect on the antenna. The other principal difference is that the modified positions of the gaps 64 and 65. described above, shift the point of maximum response to a lower frequency in the highest of the three frequency ranges for which the antenna is designed. Though the physical lengths of the outer sub-elements SI!) and 5 I0 are shorter than the physical length of th central sub-element 5|a, the antenna nevertheless still functions at the fundamental resonant frequency of the sub-element 5|a as a three-element collinear antenna, which may be confirmed by its response pattern and by the shape of its gain curve. This is believed to be due to the fact that, under such conditions, the main stubs bridging the gaps 51 and 58 do not entirely out off the outer main collinear elements 52 and 53, and that the composite result is an effective increase in the resonant lengths of the outer sub-elements Nb and 5|c to approximately the resonant length of the central sub-element 5|a.

While the antenna of Fig. 5 tends to peak in the highest frequency range at about the fundamental frequency of the central sub-element 5|a, its gain is remarkably high over a surprisingly broad range above that fundamental frequency. The reason for this is not at all clear and the theoretical factors to be considered are most complex. However, it may be that, in the upper Fig. 10, each of these main radiating elements may comprise two portions that are angularly disposed in a horizontal plane so that they still appear to be rectilinear elements as viewed in elevation from a transmitting station. The effective resonant lengths of such radiating elements are, for practical purposes, substantially equal to their projected lengths on a horizontal line in the plane of the paper in Fig. 9. Thus, the angularity shown in Fig. 10 has little, if any, practical effect on the phase relationships of the currents in the various conductors, and in this respect, they operate substantially as rectilinear elements of the lengths shown in Fig. 9. Such deviations from true rectilinear shapes have been employed commercially, though it may be questioned that any advantageous results are achieved thereby. For the purposes of the present invention, however, this optional construction represents a substantial equivalent of a rectilinear construction and may be employed in any of the various other forms of antennas shown and described herein.

Fig. 11 shows still another variation of the antenna of Fig. 5, the difference again residing merely in the manner in which the three main collinear elements in each array are connected for in-phase operation. In Fig. 11 the phasing circuit comprises of a pair of closely spaced transverse conductors 83 and 84 corresponding to the conductors BI and 62 in the antenna of Fig. 5. A pair of shorting conductors 85 and 86 respectively connect the transverse conductors 83 and 84 at spaced locations on opposite sides of their mid-points. Viewing this phasing circuit as a pair of oppositely facing phase reversing stubs, each being connected to points of zero current and maximum voltage at adjacent ends 01 and 88 of a pair of collinear elements in the upper or lower array, it will be noted that (due to the 90 phase difference between voltage and current) the currents in the stubs are a maximum and the voltages at minimum at the centers of the shortin conductors 85 and 86, and that the shorting conductors 85 and 86 are at substantially the same relatively low potentials at corresponding points along their lengths. As a result, substantially no current will pass through the portions 83a and 84a of the transverse conductors 83 and 84 extending between the shorting conductors B5 and 06 of equal electrical potential. These conductor portions 83a and 84a therefor serve no electrical function. However, they may serve a mechanical function if the shorting conductors 85 and 80 are slidably clamped to the transverse conductors 83 and 84 so that they may be moved closer together or further apart to vary the length of the oppositely facing stubs as disclosed in U. S. Patent No. 2,112,269 to Carter.

The antenna of Fig. 11 is driven in the same manner as the antennas of Figs. 5 and '7 by a pair of centrally disposed transverse feeders 09 and 90, and two additional stubs BI and 92 are interposed in the central collinear element in each array in the same manner and for the same purpose as in the antennas of Figs. and 9.

Electrically the antenna of Fig. '11 is substantially the same as two arrays of antennas of the type shown in Fig. 3 connected in parallel through the feeding conductors 09 and 90 to enhance the gain in all three of the operative frequency ranges.

Up to this point, the antennas shown and de scribed have all comprised an odd plurality of 16 generally collinear radiating elements in each array. This is preferred because it permits the feeding conductors to be connected adjacent a point of minimum voltage (maximum current) at the center of each array, and this makes it unnecessary to employ any special device or circuit to adjust the impedance of the transmission line to match the variable impedance of the antenna as the frequency of operation is changed. This is an important advantage for television reception where a receiving set may be switched back and forth from channel to channel over a wide frequency range. However, when the necessity for employing an impedance matching device in the transmission line is not objectionable, the present invention may also be employed to advantage in an array of an even plurality of generally collinear conductors, as illustrated in Fig. 12.

Referring to Fig. 12, the collinear array may comprise four collinear elements I0], I02, I03, and I04 of substantially the same resonant length. The array is preferably driven at its center by a pair of transmission line conductors or feeders I05 and I06 connected to adjacent ends of the centermost pair of collinear elements IM and I02, with a suitable impedance matching device I0'I inserted in the transmission line. The four collinear elements may then be connected for in-phase operation at the fundamental resonant frequency of the elements by a pair of quarter-wave shorted stubs I09 and H0. As will be apparent from the foregoing disclosure, the antenna will then operate in-phase as a four element collinear array at the fundamental resonant frequency of the individual collinear elements, and as a half-wave dipole at the frequency at which the entire antenna is resonant as a half-wave element.

In accordance with the present invention, gaps Hi and H2 may be provided in the centermost elements IM and I02 to divide them into subelements IOIa, IOIb, mm, and l02b. These subelements are preferably, though not necessarily, of the same resonant length. Gaps III and H2 may be bridged with small shorted stubs I I3 and H4 designed to be anti-resonant in the range of frequencies to which the sub-elements are resonant as half-wave elements. In this man ner, the sub-elements IOIa, IOIb, Him, and I02b, together with the small stubs H3 and H4, will function as a four element collinear antenna and peak at a frequency roughly twice'the fundamental resonant frequency of the main collinear elements IOI, I02, I03, and I04.

The three optimum frequencies to which the antenna of Fig. 12 will respond as described are, of course, in a quite different ratio than those at which a three-element collinear system will peak. These frequencies for the antenna of Fig. 12 will be in a ratio roughly 1:418 instead of roughly 1:3:9 as in the antenna of Figs. 3 and 4. It will also be understood that the main stubs I09 and H0 and small stubs H3 and H4 may be replaced with other equivalent anti-resonant circuits if desired.

To illustrate still another variation of standard collinear antennas to which the invention is applicable, Fig. 13 shows the invention added to another known type of antenna. This antenna operates essentially as an in-phase collinear antenna at a selected frequency, though the radiating elements are not rectilinear and do not appear so when viewed in elevation from the direction in which the antenna would be pointed.

neurone Thoughxstrikingly different: imappmrancn the antenna of; Figze laaiszessentiallyith'e sameeas the antennazof 'li'i'g; 5., but distorted: in a vertical plane;- Thus, ignoring-ion the moment:- any-"et fectsfrom: such distortion; thef. antenna comprises an upper: array: of generally collinear, radiating:- conductors: I21, I22; and I23; and a lower" corresponding array; each: adjacent: pair of individual elements in: each: arrayhaving angularly disposed portionsi that converge toward thezopposit'e' array."

Tl'ie:two -arrays1 areidr'ivenl throughr a; pair" of vertical feeding conductors we: and: I25 corrnected: to: each array. atopposite' sides Ofiacenter feed gap: IZ-Ii. The generally collinear; elements I21; I22 and I 23'? are: separated by: gaps I 2 1 and I :28; and each of "these gaps: is: bridged by an angularly' disposed and: distorted; shorted stub I am havingia pairof parallel legs ISM- and I306 and a horizontal shorting conductor I 3I'Ic that is c'ommonto each opposite pair of- 'stubs: in the two: arraysl Though its exa'cti electrical char"- a'cteristics can easily be determined onIy experi mentally because 1 of its distorted shape,- each stub It-il' will: closely approximate" a: conventional shorted stub of: similar proportions in actual' i operation: The'side I30a of each -stub- I 30 that is connected to; the central; generally: collinear element- MI is a rectilinear" extension of that central element. Though the exact points of termination of the: central element I11 andthe beginnings? of stub legs i I 3021 may be difli'cult' to determine: and, theoretically, may vary-- somewhat atdifferent frequencies; they may be: as sumed to be approximately at tlie" points desi'g nate'di x in the; drawing atitlie fimdamental reso nantfrequency of the central element's I'2 I' The-stubs:- I 30 are selected to be-v-anti' resonantaat approximately the fundamental resonant frequency of the individual; generally collinearelements I2 I22, and I23 by: varyingtliez angular relationships and lengths of tlievarious conductors and comparingthe response patternof the antenna with one of thetype shown in Figz' 5.

In accordance with the present invention an additionalpair ofsma'ller stubs: I31 and I37; is interposed in each central 'radiating element I Z I dividing it into three sub-elements I2 'I'a, I'Z'I b, and l-2 l'c. These sub elements' may-beef substantially the same individual overall length (including' feed gap L I26 m sub-element I 2"Ia')'-, or their relative lengths may" be; varied somewhat as in the case of theother embodiments of the invention described above. Similarly, theproportions and developed length off thei'small stubs l3 l and I 32- may" bevaried within the range of fundamental frequencies of the three sub' e'le' ments separated thereby: Also; thefsmall stubs island I32 may extendtoward each other in a vertical plane, assh'own', or may bedisposed' at anyanglei To clarify the close operational similarity of the antennas of Figs; 5' and 135; it-iis-to, benoted that; for practical" purposes; only'tlie" horizontal components of theradiating elements I21; I22, and I are efiective as radiating (or receiving) elements f for. azt'elevision wave} wnienes liori'zom tally polarized;- Ac'cordingly; in Fig: 1'4; these projected: lengths are'shown' with corresponding reference; characters applied thereto: When the antenna of" Fig: I3 is: operating a: the fundamental frequency of each complete array; func tioningsas? a:ha1f-wave:dipo1e; tide-currentim the antenna; is: approximately represented by the curve I1 7 in :E'ig; A'tthe; fundamental resonant fre'que'ncy-=- of" the individual; generally collinear element/s IZII, I22; and I23; the currents'ih-these radiating elementswill be approximatelyin: phase: asrepresented by the curves I2 in Fig; 14'. At still higher frequencies approximating the resonant frequencies of the individual sub el'e- I ment's I2 I'a, IZ -Ib', andIZIc, the currents therein will be-substantial1yin-phase as represented by the curvesels in-Figi 14. (Compare current'rel'ationsliips in F'ig; 3.) As is-the case withthe antennas of Figs. 3, 4, 5, 9-, and l 1,'the antenna ofFig. 13 will peak atthree optimum frequencies inthe approximate ration-of 1:3:9. It willbe 'efieetive ovena -liinitedrange above and below each optimum frequency, though my tests have shown the gain of the antenna of IB to be substantiallylower overthe entire usefulranges thereofthan-the'gain of the preferred formshown in-Figt 5;-

Inall seven-of the antennas of Figs-; 3, 4} 5', 9, 1'1; 12; and'13; gapsare providedin the'center most", maincoll'inearelement' or elementsof each array" to' form a number of sub-elements; and these gaps are bridged byanti-resonant circuits tuned'to-a frequency in the rangeof' the fund'a' mental resonant frequencies of the'sub-element's;

I'n all seven'ofthese-antennas; theresult is to render them responsive inanadditional, higher frequency range and' thus increase their-utility for television or radio reception. It will'beap preciated, therefore, that I haveprovidedanovel scheme for modifying antennas designed for operation as a*- half-wave dipole in a-' low frequency range and as acollinear antenna in an inter-mediate frequency range; by incor orating additional circuits which produce in-ph'aseco'l linear-operationo'fa portion of th'eantenna in a third; higher frequency range, without" inter-- fering in' any-material-respect Withtlie' operation in the low-and? intermediate ranges: It wiilfalso be appreciated from the several" emb'o diments of thetinvention'disclosedherein; thatthe invention is applicable. to'a variety of forms andvari'ations of.conventionalcollinear antennas, involving dif ferent systems'for -effecting iii-phase operation in the intermediate frequency range; Accordingly,

the invention is 3 not intended to" be limite'd to. the

particular details shown and describedfor illustrative purposes, except as may be required by the terms of the appended claims.

' Havingdescribed my invention, Ifclaim:

1;. An antennacomprising 1 a plurality offradi; ating" conductor elements of"substantial1y; equal resonant length. disposed in longitudinallyspaced relationship; means connecting said conductor elements for substantially in-phase operationv as acollinear array at" one frequency, and means interposedin' at" least one of said, conductor elev ments for connecting portions. thereof for in? phase operation: as a collinear array, at. a substantiall'yhigherfrequency.

2;, An antenna comprising a plurality; offradi 'ating' conductor" elements of substantially equal resonantlengthdisp'ose'd'in longitudinally spaced relationship, circuit means connecting, said conductorelements' a's'ca' collinear arrayfbn substane tia'llyiin-phas'e' operation as. half'T-wave. elements at a" selected frequency, a plurality of 'anti-reso nant'circuits interposed'in and,forming apart v 3. An antenna comprising a plurality of radiating conductor elements of substantially equal resonant length disposed in longitudinally spaced relationship, circuit means connecting said conductor elements as a collinear array for substantially in-phase operation as half-wave elements at a selected frequency, a plurality of anti-resonant circuits interposed in and forming a part of at least one of said conductor elements to divide it into three conductor portions, said antiresonant circuits having a relatively low impedance at said selected frequency and maximum impedance at a substantially higher frequency substantially corresponding to the half-wave resonant frequency of at least one of said three conductor portions.

4. An antenna comprising a plurality of radiating conductor elements of substantially equal resonant length disposed in longitudinally spaced relationship, circuit means connecting said conductor elements as a collinear array for substantially in-phase operation as half-wave elements at a selected frequency, a plurality of anti-resonant circuits interposed in and forming a part of at least one of said conductor elements to divide it into three conductor portions, said antiresonant circuits having a relatively low impedance at said selected frequency and maximum impedance at a substantiall higher frequency substantially corresponding to the half-wave resonant frequency of the one of said conductor portions extending between said anti-resonant circuits.

5. An antenna comprising a plurality of conductor elements disposed in longitudinally spaced relationship, means connecting said elements as a collinear array for substantially in-phase operation as half-wave elements at a selected frequency, and at least one pair of anti-resonant circuits respectively interposed in conductor elements of said array on opposite sides of the center of the array, said anti-resonant circuits being selected to have a relatively low impedance at said selected frequency and substantially infinite impedance at a substantially higher frequency, and said anti-resonant circuits being interposed in said array at locations selected to produce substantially in-phase operation at said higher frequency of portions of said conductor elements connected to said anti-resonant cir- O cuits.

6. An antenna comprising a plurality of conductor elements disposed in longitudinally spaced relationship, means connecting said elements as a collinear array for substantially in-phase operation as half-Wave elements at a selected frequency, including a pair of feeding conductors connected to said array adjacent the center thereof, and at least two anti-resonant circuits respectively interposed in said array at locations symmetrically disposed on opposite sides of said feeding conductors for producing substantially in-phase operation at a frequency substantially higher than said selected frequency of portions of said array to which said anti-resonant circuits are connected.

'7. An antenna comprising an array of at least three radiating conductor elements of substantially equal resonant lengths disposed in longitudinally spaced relationship, phasing means connecting said elements for substantially inphase operation as half-wave elements at a selected frequency, and at least two anti-resonant circuits respectively interposed in said array inwardly between said phasing means, said antiresonant circuits having a relatively low impedance at said selected frequency and substantially infinite impedance at a substantially higher frequency and being symmetrically interposed in said array on opposite sides of the center thereof at locations selected to produce substantially inphase operation at said higher frequency of the conductor portions of said array extending between said phasing means.

8. An antenna comprising an array of an odd plurality of conductor elements in longitudinally spaced relationship, means connecting said elements for substantially in-phase operation as half-wave elements at a selected fundamental frequency, the central one of said elements having a central feed gap and a pair of feeding conductors connected thereto at opposite sides of said feed gap, said central one of said elements having a pair of additional gaps therein respectively disposed on opposite sides of said feed gap, and anti-resonant circuits bridging said additional gaps, said anti-resonant circuits having a relatively low impedance at said selected frequency and a substantially infinite impedance at a substantially higher frequency to produce substantially in-phase operation at said higher frequency of conductor portions separated by said additional gaps.

9. An antenna according to claim 8 in which there are two of said arrays of substantially identical form disposed in vertically spaced relationship and connected in parallel by said feeding conductors, the means for connecting the longitudinally spaced conductor elements in each array for in-phase operation at said selected fundamental frequency comprising vertically extending shorted stubs with a single conductor shorting each pair of corresponding stubs in the upper and lower arrays, and in which said anti-resonant circuits in each array are shorted stubs separated from the corresponding stubs of the other array.

10. An antenna according to claim 8 in which there are two of said arrays of substantially identical form disposed in vertically spaced rela tionship and connected in parallel by said feeding conductors, the means for connecting the longitudinally spaced conductor elements in each array for in-phase operation at said selected fundamental frequency comprising vertically extending shorted stubs with a single conductor shorting each pair of corresponding stubs in the upper and lower arrays, and in which said antiresonant circuits in each array are shorted stubs separated from the corresponding stubs of the other array, the stubs constituting said antiresonant circuits being disposed in horizontal planes.

11. An antenna according to claim 8 in which there are two of said arrays of substantially identical form with the central one of said longitudinally spaced conductor elements in each array transversely offset from the adjacent outer conductor elements in that array and in substantial longitudinal alignment with the corresponding outer conductor elements in the other array, the longitudinally spaced conductor elements in each array being connected for in-phase operation at said selected frequency by generally transverse phasing conductors that are substantially half-wave elements at said selected frequency, and in which said anti-resonant circuits are shorted stubs.

12. An antenna according to claim 8 in which there are two of said arrays of substantially identical form with the central one of said lon tudinally spaced conductor elements in each array transversely offset from the adjacent outer conductor elements in that array and in substantial longitudinal alignment with. the corresponding outer conductor elements in the other array, the longitudinally spaced conductor elements in each array being connected for in-phase operation at said selected frequency by generally transverse phasing conductors that are substantially half-wave elements at said selected frequency, and each of said longitudinally spaced conductor elements in each array comprising two substantially equal portions that are angularly disposed in a plane generally transverse with respect to said phasing conductors, and in which said anti-resonant circuits are shorted stubs.

13. An antenna according to claim 8 in which there are two of said arrays of substantially identical form disposed in vertically spaced relationship and connected in parallel by said transverse feeding conductors, the means for connecting the longitudinally spaced conductor elements in each array for in-phase operation at said selected frequency comprising shorted stubs disposed opposite and extending vertically toward the corresponding stubs in the other array with the shorting members of the stubs of each opposite pair spaced apart, and in which said anti-resonant circuits in each array are shorted stubs.

14. An antenna according to claim 8 in which there are two of said arrays of substantially identical form disposed in vertically spaced relationship and connected in parallel by said transverse feeding conductors, the means for connecting the longitudinally spaced conductor elements in each array for in-phase operation at said selected frequency comprising shorted stubs disposed opposite and extending vertically toward the corresponding stubs in the other array with the shorting members of the stubs of each opposite pair spaced apart and connected together at their extremities by extensions of the vertically extending portions of said stubs, and L in which said anti-resonant circuits in each array are shorted stubs.

15. An antenna according to claim 8 in which there are two of said arrays of substantially identical form disposed in vertically spaced relationship and connected in parallel by said feeding conductors, adjacent longitudinally spaced conductor elements in each array having conductor portions extending toward the other array in converging relationship, the means for connect- H ing the longitudinally spaced conductor elements in each array for in-phase operation at said selected frequency comprising shorted stubs each having a pair of spaced conductors extending toward the corresponding stubs of the other array along inclined parallel lines, each opposite pair of said stubs being connected to and shorted by a common horizontal conductor, and one of the pair of spaced conductors of each of said stubs being a rectilinear continuation of the central one of said longitudinally spaced conductor elements, and in which said anti-resonant circuits in each array are shorted stubs separated from the corresponding stubs of the other array.

16. An antenna according to claim 8 in which there are two of said arrays or substantially identical form disposed in vertically spaced relationship and connected in parallel by said feeding conductors, adjacent longitudinally spaced con- 'du'ctor elements in portions extending toward the other array in coneach array having conductor verging relationship, the means for connecting the longitudinally spaced conductor elements in each array for in-phase operation at said selectt ed frequency comprising shorted stubs each having a pair of'spaced conductors extending toward the corresponding stubs of the other array along inclined parallel lines, each opposite pair of said stubs being connected to and shorted by a common horizontal conductor and one of the pair of spaced conductors of each of said stubs being a rectilinear continuation of the central one of 'said longitudinally spaced conductor elements,

and in which said anti-resonant circuits in each array are shorted stubs separated from the corresponding stubs of the other array, the stubs constituting said anti-resonant circuits being disposed in a vertical plane.

17. An antenna comprising an array of an even plurality of radiating conductors of substantially equal resonant lengths disposed in longitudinally spaced relationship, means including a pair of transmission line conductors connecting said elements of said array for substantially in-phase operation as half-wave elements at a selected "frequency, and a pair of anti-resonant circuits respectively interposed in radiating conductors of said array on opposite sides of said transmission line conductors, said anti-resonant circuits having a relatively low impedance at said selected frequency and substantially infinite impedance at a substantially higher frequency and being interposed at location selected to produce substantially in-phase operation at said higher fre- 1y equal resonant lengths disposed in longitudinally spaced relationship, means including a pair -of transmission line conductors connecting said elements of said array for substantially in-phase operation as half-wave elements at a selected -frequency, and a pair of anti-resonant circuits respectively interposed in radiating conductors of said array on opposite sides of said transmission line conductors, said anti-resonant circuits hav ing a relatively low impedance at said selected frequency and substantially infinite impedance at a substantially higher frequency and being interposed at locations selected to produce substantially in-phase operation at said higher frequency of four radiating conductor portions each of which is connected to one of said anti-reso nant circuits.

19. An antenna comprising an array of an even plurality of radiating conductors of substantially equal resonant lengths disposed in longitudinally spaced relationship, phasing means con necting pairs of said elements for substantially .in-phase operation as half-wave elements at a selected frequency, including a pair of transmission line conductors respectively connected to adjacent ends of the centermost pair of said ele said elements for dividing each into separated circuits being a shorted stub having a relatively low impedance at said selected frequency and substantially infinite impedance at a substantially higher frequency in the range in which said inner and outer parts are resonant as half-wave elements for producing substantially in-phase operation at said higher frequency of said inner and outer parts.

20. An antenna comprising an odd plurality of conductor elements in longitudinally spaced relationship, said elements being resonant as halfwave elements at substantially the same selected fundamental frequency, a plurality of anti-resonant circuits tuned to substantially the same selected frequency and respectively bridging the gaps between adjacent pairs of said conductor elements, the central one of said conductor elements having a pair of gaps therein respectively located on each side of its center to divide it into three longitudinally spaced portions resonant as half-wave elements in a substantially higher frequency range than said selected frequency, and a pair of anti-resonant circuits bridging said gaps in said central conductor element for eifecting substantially iii-phase operation of said longitudinally spaced portions thereof in said higher frequency range.

21. An antenna comprising an odd plurality of generally collinear, radiating elements in longitudinally spaced relationship, said elements being resonant as half-wave elements at substantially the same selected fundamental frequency, a p1urality of anti-resonant circuits tuned to substantially the same selected frequency and respectively bridging the gaps between adjacent pairs of said collinear elements, a pair of feeding conductors connected to said central collinear element at spaced points adjacent the center thereof, a pair of gaps in said central collinear element respectively located on opposite sides of said pair of feeding conductors to divide said central collinear element into a plurality of longitudinally spaced collinear portions resonant as half-Wave elements to fundamental frequencies in a range from about three to four times said selected fundamental frequency, and a pair of anti-resonant circuits tuned to a frequency in said range and respectively bridging said additional gaps in said central collinear element.

22. An antenna comprising an odd plurality of generally collinear, radiating elements in iongitudinally spaced relationship, said elements being resonant as half-wave elements at substantially the same selected fundamental frequency, a plurality of phase reversing stubs tuned to substantially the same selected frequency and respectively bridging the gaps between adjacent pairs of said collinear elements, a pair of feeding conductors connected to spaced points adjacent the center of the central one of said collinear elements, a pair of gaps in said central collinear element respectively located on opposite sides of said pair of feeding conductors for dividing said central collinear element into three longitudinally spaced collinear portions which are resonant to frequencies in a range substantially higher than said selected frequency, and an additional pair of phase reversing stubs tuned to a frequency in said range and respectively bridging the gaps in said central collinear element.

23. An antenna comprising an odd plurality of generally collinear, radiating elements in longitudinally spaced relationship, said elements being resonant as half-wave elements at substantially the same selected fundamental frequency, a plurality of phase reversing stubs tuned to substantially the same selected frequency and respectively bridging the gaps between adjacent pairs of said collinear elements, the central one of said collinear elements having a center gap therein, a pair of feeding conductors connected to said central collinear element at opposite sides of said center gap, a pair of additional gaps in said central collinear element respectively located on opposite sides of said pair of feeding conductors for dividing said central collinear element into a plurality of spaced collinear portions, and an additional pair of phase reversing stubs respectively bridging said pair of additional gaps and tuned to a frequency in the range in which said spaced collinear portions are resonant as half-wave elements.

24. An antenna comprising three generally collinear, radiating elements in longitudinally spaced relationship, each of said collinear elements being resonant as a half-wave element at a selected frequency in the range of about 174 to 216 megacycles, a plurality of phase reversing stubs tuned to frequencies in said range and respectively bridging the gaps between adjacent pairs of said collinear elements, the central one of said collinear elements having a center gap therein, a pair of feeding conductors connected to said central collinear element at opposite sides of said center gap, a pair of additional gaps in said central collinear element respectively located on opposite sides of said pair of feeding conductors to divide said central collinear element into three longitudinally spaced collinear portions each resonant as a half-wave element at a frequency in the range of 470 to 890 megacycles, and an additional pair of phase reversing stubs tuned to a frequency in the range of 470 to 890 megacycles and respectively bridging said pair of additional gaps, said resonant frequency values being selected so that the three collinear elements and the stubs connected thereto will operate substantially as a half-Wave dipole at a frequency in the range of 54 to 88 megacycles, and will operate substantially as a three element collinear antenna in both the intermediate and highest of said ranges.

25. An antenna comprising an upper array of three generally collinear radiating elements in longitudinally spaced relationship, said elements being resonant as half-wave elements at substantially the same selected frequency, a lower corresponding array spaced from said upper array in transversely aligned relationship therewith, a pair of parallel transverse feeding conductors connecting symmetrically spaced points adjacent the center of said upper array to corresponding points on said lower array, two pairs of generally transverse phasing conductors respectively located on opposite sides of said feeding conductors, said phasing conductors connecting said collinear conductors of both the upper and lower arrays for substantially in-phase operation at their resonant frequency, the central one of said collinear elements in each of said arrays having a pair of gaps therein respectively located on opposite sides of said pair of feeding conductors for dividing said central collinear element into three longitudinally spaced, generally collinear portions, and a pair of anti-resonant circuits in the central collinear element of each of said arrays respectively bridging the gaps between said collinear portions, each of said anti-resonant circuits being tuned to a frequency in the range in which said collinear portions are resonant as half-wave elements.

26. An antenna comprising an upper array of three generally collinear radiating elements in longitudinally spaced relationship, said elements being resonant as half-wave elements at substantially the same selected frequency, a lower corresponding array spaced from said upper array in transversely aligned relationship therewith, a pair of parallel transverse feeding conductors connecting symmetrically spaced points adjacent the center of said upper array to corresponding points on said lower array, two pairs of closely spaced, generally transverse, phasing conductors respectively located on opposite sides of said feeding conductors, each pair of said phasing conductors connecting the adjacent ends of an adjacent pair of said radiating elements in said upper array to the corresponding ends of corresponding rediating elements in said lower array, and at least one shorting conductor associated with each pair of phasing conductors for connecting them together adjacent their midpoints and forming oppositely facing phase reversing stubs for said upper and lower arrays, the central one of said collinear elements in each of said arrays having a pair of gaps therein respectively located on opposite sides of said pair of feeding conductors for dividing said central collinear element into three longitudinally spaced, generally collinear portions, and a pair of antiresonant circuits in the central collinear element of each of said arrays respectively bridging the gaps between said collinear portions, each of said anti-resonant circuits being tuned to a frequency in the range in which said generally collinear portions are resonant as half-wave elements.

27. An antenna comprising an upper array of three generally collinear radiating elements in longitudinally spaced relationship, said elements being resonant as half-wave elements at substantially the same selected frequency, a lower corresponding array spaced from said upper array in transversely aligned relationship therewith, a pair of parallel transverse feeding conductors connecting symmetrically spaced points adjacent the center of said upper array to corresponding points on said lower array, two pair of closely spaced generally transverse phasing conductors respectively located on opposite sides of said feeding conductors, each pair of said phasing conductors connecting the adjacent ends of an adjacent pair of said radiating elements in said upper array to the corresponding ends of corresponding radiating elements in said lower array, and a shorting conductor associated with each pair of 46 phasing conductors for connecting them together adjacent their mid-points and forming oppositely facing phase reversing stubs for said upper and lower arrays, said shorting conductor being a common element of each oppositely facing pair of said stubs, the central one of said collinear elements in each of said arrays having a pair of gaps therein respectively located on opposite sides of said pair of feeding conductors for dividing said central collinear element into three longitudinally spaced, generally collinear portions, and a pair of anti-resonant circuits in the central collinear element of each of said arrays respectively bridging the gaps between said collinear portions, each of said anti-resonant circuits being tuned to a frequency in the range in which said collinear portions are resonant as half-wave elements.

28. A television antenna conductor adapted to serve as part of a collinear member of a collinear array of conductors, comprising a rod of conductive material formed into two axially aligned portions separated by a gap and connected across said gap by a generally U-shaped portion, the opposite extremities of said rod being formed into loops for receiving mounting elements, said loops being disposed in a plane normal to the plane defined by said U-shaped portion for receiving hinge pintles extending parallel to the plane of said U-shaped portion.

29. The device of claim 28 in which said axially aligned portions are of substantially the same length, the actual length of said rod is between 11 and 16 inches and its developed length is between 18 and 30 inches.

30. The device of claim 28 in which said aligned portions are of substantially the same lengthand the developed length of said U-shap'ed portion is from about to about of the sum of the lengths of said aligned portions.

LEWIS H. FINNEBURGH, JR.

References Cited in the file of this patent UNITED STATES PATENTS 

